Building mathematical graph of AC-DC voltage converter

Question

    I build the math function that describes the graphical operation of an electronic Wheatstone bridge (full-wave rectifier). I arrived at the following solution I created a generative wave function (to match what we have from energy providers 60 Hz).

<<Generative: $\ sin(T*\ 2pi*Hz) $

where T is the time variable in the interval 0 .. N

2 represents a full wave neg. and pos. = hz

$\ pi$ is the constant used to aim wave phase shift by one Pi (calibration)

variable Hz is determined by the number of oscillations in time unit, in this case 60 Hz/sec..

    Math absolute value function works exactly like diodes (eg. Wheatstone bridge), and applied to the generative function above, the graphic in this moment looks like.

<<With full-wave rectifier: $\ abs(sin(T*\ 2pi*Hz)) $

    What I do not know, and i need some help there is how to represent graphical dischage of a capacitor applied to this graph, I do not understand how I could conceive a composed function so that when current sine value decrease below the max peak of it , to decress linear to the next wave at about 0.75 (sqrt (2) / 2) amplitude.

I want to understand this, will help me a lot with how all electronic components works, next stage will be Fourier analysis.

Thanks in advance!